Calculators built on real numbers
Interactive tools from a practicing engineer — the math is always shown, the defaults come from documented real-world data, and your inputs live in the URL so you can share or save your exact scenario. No popups, no paywalls, no email traps.
PoolCalc Salt conversion payback, dosing and volume — defaults from a documented real conversion.
DriveCalc Month-by-month loan, depreciation and cash-flow simulation — not payment-table guesswork.
PlaneCalc Fixed and variable operating cost, blended $/hr at your real annual utilization.
Why these are different
Most calculators online are content-farm filler — a thin form wrapped around a guess. These are built by an engineer who does modeling and simulation for a living: every formula is visible in a "see the math" panel, the defaults trace back to real documented projects rather than round numbers, and the models are tested against validated references. About the author · Read the methodology.